drm/amdgpu: allow specifying vm_block_size for multi level PDs v2

This patch allows specifying the vm_block_size even when multi level
page directories are active.

v2: fix signed/unsigned compare warning
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -1162,20 +1162,8 @@ static void amdgpu_check_block_size(struct amdgpu_device *adev)
 	if (amdgpu_vm_block_size < 9) {
 		dev_warn(adev->dev, "VM page table size (%d) too small\n",
 			 amdgpu_vm_block_size);
-		goto def_value;
+		amdgpu_vm_block_size = -1;
 	}
-
-	if (amdgpu_vm_block_size > 24 ||
-	    (amdgpu_vm_size * 1024) < (1ull << amdgpu_vm_block_size)) {
-		dev_warn(adev->dev, "VM page table size (%d) too large\n",
-			 amdgpu_vm_block_size);
-		goto def_value;
-	}
-
-	return;
-
-def_value:
-	amdgpu_vm_block_size = -1;
 }
 
 static void amdgpu_check_vm_size(struct amdgpu_device *adev)

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -2600,18 +2600,21 @@ void amdgpu_vm_adjust_size(struct amdgpu_device *adev, uint32_t vm_size,
 	adev->vm_manager.max_pfn = (uint64_t)vm_size << 18;
 
 	tmp = roundup_pow_of_two(adev->vm_manager.max_pfn);
+	if (amdgpu_vm_block_size != -1)
+		tmp >>= amdgpu_vm_block_size - 9;
 	tmp = DIV_ROUND_UP(fls64(tmp) - 1, 9) - 1;
 	adev->vm_manager.num_level = min(max_level, (unsigned)tmp);
 
 	/* block size depends on vm size and hw setup*/
-	if (adev->vm_manager.num_level > 1)
-		/* Use fixed block_size for multi level page tables */
-		adev->vm_manager.block_size = 9;
-	else if (amdgpu_vm_block_size == -1)
+	if (amdgpu_vm_block_size != -1)
 		adev->vm_manager.block_size =
-			amdgpu_vm_get_block_size(vm_size);
+			min((unsigned)amdgpu_vm_block_size, max_bits
+			    - AMDGPU_GPU_PAGE_SHIFT
+			    - 9 * adev->vm_manager.num_level);
+	else if (adev->vm_manager.num_level > 1)
+		adev->vm_manager.block_size = 9;
 	else
-		adev->vm_manager.block_size = amdgpu_vm_block_size;
+		adev->vm_manager.block_size = amdgpu_vm_get_block_size(tmp);
 
 	if (amdgpu_vm_fragment_size == -1)
 		adev->vm_manager.fragment_size = fragment_size_default;